Mechanistic insight into the role of the aspect ratio of nanofillers in the gas barrier properties of polymer nanocomposite thin films†

The introduction and processing parameters of 2D graphene flakes into a polymer matrix were altered in order to understand the impact of dispersed flake geometry on the physical properties of nanocomposites. It has been highlighted in this study that the intermolecular interaction plays a critical role in the structure–properties of polymeric barrier films where the experimental results were validated by appropriate models. The microstructural analysis of nanocomposite films revealed that 2D nanofillers predominantly existed in an agglomerated state inside the polymer matrix and the size of the nanofiller cluster linearly increased as a function of loading percentage. We have illustrated that the immobilization of nanotubes into graphene flakes creates a porous hierarchical geometry which facilitates the polymer chains to diffuse into hybrid nanofillers to produce a uniform phase segregated morphology. Our findings underscore the significance of the aspect ratio of dispersoids in influencing the barrier properties of nanocomposite flexible films.